The technical field of this invention concerns apparatus and systems for the extrusion of capsules, hollow fibers and the like.
Various extrusion apparatus are known in the art, primarily for use in fabricating hollow fibers. Typically, such extrusion systems include a spinneret with concentric bores. A fiber-forming material (e.g., a polymeric casting solution) is supplied to the outer bore while a coagulant or other fluid is delivered to the inner bore. As the two fluids flow through the nozzle, a hollow core extrudate is formed.
Spinneret-based systems can be difficult to operate. Most often, a manual "pulling" step is required to initiate the extrusion process. Even with careful cleaning, they are prone to clogging problems. Moreover, their sluggish response to changes in flow rate or fluid composition make it difficult to modify the extrudate via process controls.
Extrusion systems have also been proposed for the fabrication of living cell or tissue capsules, for therapeutic implants, bioreactors and the like. Unfortunately, existing techniques often produce macrocapsules with seams. This is due to the fact that an open end of the macrocapsule necessarily results from the macroencapsulation methods. For many applications, it is desirable to have a seamless capsule.
Thus, there exists a need for improved apparatus and systems for production of hollow fibers and/or macroencapsulation of cells. Encapsulation systems that enable production of fibers and encapsulated vehicles in an automated fashion, which permit the usage of a wider range of materials, and/or which provide more reliable and/or seamless closure, would satisfy a long felt need in the art.